Video would not be transformed in any way, and discussion would take place on reddit or other discussion platforms.
So you are copying someone else's video and reposting it verbatim and in full in vimeo, without adding any additional content of your own?
What is even the need for it? If you want to discuss the video in Reddit or similar, you can link to the original video instead of your copy.
The usual way that fair use is used is when you include the relevants parts of the work being criticized as part of your video. There are other points to take into consideration; IP lawsuits are very specific of the details of the works involved (for examples it could be easier to consider fair use the inclusion of the full original work if it were a short one that if it were a long one) so it is difficult to give an absolute "yes" or "no" answer.
But what you attempt to do seems highly problematic. If your argument were valid, what would prevent me from setting an URL to download the latest Hollywood blockbuster because I am commenting about it on Reddit? Imagine that I start selling copies of "The Avengers XXII: A day at the Park"1 adding just a note at the end saying "I like this movie, but they played frisbee a lot too much" as opinion/commentary/criticism... do you think that it would qualify as "fair use"?2
Coupled with the fact that it seems that copying the video seems not necessary for commenting on it (again, just link to the source) I would consider more prudent3 not copying it.
1Well, technically I would say that I were selling my opinion (which is perfectly legal), with the film included only as "fair use" to provide context to my opinion.
2Answer: No, it would not.
3I am not a lawyer, I am not your lawyer, and this site does not provide legal advice.